Shutter for cinematographic apparatus



April 1931- A. L. v. c. DEBRIE 1,800,088

SHUTTER FOR CINEMATOGRAPHIC APPARATUS Filed Feb. 10, 1928 Ma ra/e. i l/Wg 'L. KC 0619/6 ayf ym', flw, w wl- 4144.

I Xfs Patented Apr. 7, 1931 UNITED STATES PATENT OFFICE ANDRE LEON VICTOR CLEMENT DEBBIE, OF PARIS, FRANCE SHUTTER FOR CINEMATOGBAPHIC APPARATUS Application filed February 10, 1928, Serial No. 253,474, and in France February 21, 1827.

My invention has for its object an improved shutter for cinematographic apparatuses which allows the film to be impressed or exposed automatically to a degree which is constant whatever the speed of rotation of the mechanism of the cinematographic apparatus.

In view of this the shutter instead of being constituted by the usual single indentated disc comprises two preferably similar inden- 'tated discs disposed side by side and of which one is keyed on the usual controlling shaft and the other is mounted freely on its shaft which is driven by the former one and may rotate with reference to it under the action of a device submitted to the influence of the centrifugal force in a manner such that at the greater speeds,-the indentations of the two discs are in complete coincidence so that the maximum amount of light may pass through them. On the contrary as the apparatus moves more slowly, the indentations are shifted more and more one with reference to the other so as to cause the amount of light passing through the shutter to diminish when the speed decreases.

I have shown by way of example on appended drawings a form of execution of my invention wherein:

Fig. 1 is a general view of the device when at rest, I

Fig. 2 is a diagrammatical side view partly sectional of a centrifugally acting part respectively in its operative and its inoperative 35 position.

Fig. 3 is a partly sectional side view at an enlarged scale.

Fig. 4 shows two half sections taken at 90 with reference to Fig. 3, the upper halfsection showing the device in its inoperative position and the lower half-section showing it at midway between its extreme positions.

The shutter comprises two indentated discs 1 and 3 of which the former is keyed to the controlling shaft 2 and the latter is secured to a sleeve 4 freely mounted on the shaft 2 and abutting against the disc 1. The two discs may be more or less identical so that under certain conditions to be ascertained hereinafter, their indentations may be in perfect coincidence. The discs 1 and 3 may however not be exactly similar as shown. On the inside of the disc 1 are disposed in alinement with each other twothreaded rods having a great pitch, and rotatabl held in the bearings 7 and 8 secured to the isc 1, the axis of the two rods passing through the center of rotation of the disc. To each rod and near the said center is keyed a bevel pinion 9 or 10.

Besides two nuts 11 and 12 are adapted to slide along the two rods and their shape is such that they cannot rotate round the latter. The nuts are connected together through the springs 13 and 14 and engage the threads of rods 5 and 6 either through suitable tappings or through a projection such as 15.

Lastly in a recess 16 provided in the center of the disc or plate 3 is secured a bevel pinion 17 engaging the bevel pinions 9 and 10 whereby when rotating the disc 3 moves to gether with the disc 1; a pin 18 passing through the shaft 2 keeps the disc 3 in contact with the disc 1.

The working is as follows: When at rest the indentations of the two discs 1 and 3 are shifted one with reference to the other (Fig. 1) so as to leave only the minimum aperture allowed for the shutter. When the shaft 2 rotates, it draws the disc 1 along with it and also the disc 3 through the pinions 9 and 10 and pinion 17. As the speed of shaft 2 increases, the nuts 11 and 12 have a tendency under the action of the centrifugal force to move away from the center and as they cannot rotate they cause the threaded rods 5 and 6 to rotate in opposite directions and consequently the pinions 9 and 10 to revolve in op posite directions. The latter mesh with the wheel 17 which rotates and causes the disc 3 to rotate with reference to the shaft 2 and the disc 1 in a direction such that the aperture afforded by the shutter increases. For a sufiicient speed of the shaft, the two indentations of the discs are in coincidence and the shutter opening is maximum. A stop 19 borne by the disc'3 is adapted to meet at this moment the edge of the disc 1 so as to prevent when the speed increases further, the

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a ing. If this were the case the opening of the shutter would then diminish by a. shifting in the reverse direction of the indentations of the discs. The same result could also be obtained by making the nuts 11 and 12 a :1 against the bearings 8.

springs13 and 14 have a tendency to bring trek the two discs towards their initial position when the speed decreases and conse m qnently to close the shutter aperture. What I claim is: 1. A shutter for cinematographic apparatuses com rising a driving shaft, a first indentated disc keyed thereto, a second in- 15 dentated disc, mounted freely on the driving shaft, the indentations of the discs being normally in only partial coincidence, two alined threaded rods rotatably secured to the first disc, over a diameter thereof, a bevel pinion,

keyedto the inner end of each rod, 2. toothed pinion coaxial with and keyed to the second disc and meshing with the two bevel pinions, aglongitudinally movable nut cooperating with each rod, means for preventing the said nuts from rotating, and springs urging the nuts together.

2. A shutter for cinematographic appa-. ratuses comprising a driving shaft, a first indentated disc secured thereto, a second indentated disc mounted freely on the driving shaft, the indentations of the discs when at rest being in only partial coincidence, a gear work connecting the two discs and adapt ed to make them rotate together and an independent centrifugal device slidably mounted with reference to the first disc and positively controlling the gear work for.

. shifting the'second disc angularly with ref- 7 erence to the first .one.

o 3. A shutter for cinematographioa pparatuses comprising a driving shaft, a firstindentated disc secured thereto, a second indentat'ed disc mounted freely on the driving shaft, the indentations of the discs when at rest being in only partial coincidence, a nut adapted to slide radially over the first disc under the action of the centrifugal force, a springeurgin said nut back, a long-pitched t readed ro rotatably supported by the 5o first disc and cooperating with the nut, and

meansfor positively controlling the angular position-of the second disc on the shaft; through the rotation of the threaded'rod. In testimony whereof I have signed my name to this specification.

mums Lion VICTOR CLEMNT mm- J 

